Counting tube read out system



United States Patent The present invention relates to counting tubes and, more particularly, to circuitry for reading digital information from counting tubes of the type comprising a common electrode (e.g. a central anode) anda plurality of sequence electrodes (e.g. aplurality of surrounding cathodes) within a discharge gas. The gas conducts or glows between the common electrodes and a selected sequence electrode when a predetermined voltage is applied. Under the control of guide electrodes,'which restrict the discharge to a selected region in a given digital position that represents a given count, the glow moves from position to position in response to input signals; a a

At a particulardigital position, a glow generated by electron discharge between the common electrode and the selected sequenceelectrode, results in a voltage drop across an associated load resistor. A typical information storage system comprises one or more channels each including one or more counting tubes. Inthepast, the serial reading of information from such counting tubes has required a myriad of load irnpedances in correspondence with the myriad of sequence electrodes of the many counting tubes and in association with necessarily complex switching.

The object of the present invention is to secure an unprecedented simplification of read out circuitry of the foregoing type by applying a carrier signal to the common electrode (e.g. anode) of one or more counting tubes.

Since the counting tube essentially is characterized by constant voltage operation, the carrier signal will reappear at and serve to identify'a selected sequence electrode (e.g. selected cathode). In consequence, sequence electrodes of different counting tubes may be connected to relatively few load impedances that serve several counting tubes at once and may be coupled to information sensing circuitry in a manner that obviates complex switching.

Other objects of the present invention will in part be obvious and will in part appear hereinafter.

For a complete understanding of the present invention, reference should be had to the following detailed disclosure, taken in connection with the accompanying drawings wherein:

Figure 1 illustrates an exemplary counting tube useful in accordance with the present invention;

Fig. 2 illustrates an exemplary circuit for driving the counting tube of Fig. 1 in response to input countin pulses; and v Fig. 3 illustrates a circuit for reading information from one or more counting tubes in accordance with the present invention.

The counting tubes of the illustrated embodiment of i I the present invention are multi-cathode glow tubes of the type shown in Fig. 1 and driven in Fig. 2. As shown in Fig. 1, each counting tube includes an anode 20, ten cathodes 22 having independent leads 24, ten first guides 26 all connected through a first guide ring 28 to a lead 30, and ten second guides 32 all connected through a second guide ring 34 to a lead 36. As shown, the cathodes, first 2,937,318 Patented May 17, 1960 2 guides and second guides are interspersed in cyclic order and are disposed within a hermetic envelope containing an inert gas such as argon, neon, krypton, etc. Under the control of guides 26 and 32, the gas conducts, in one of ten restricted regions beneath a dial or bezel 38. Bezel 38 provides translucent positions 40, one of which at any given'time is illuminated by a glow generated below it by discharge between anode 20 and; a selected cathode 22.

In a typical case, the first and second guides normally are held :at plus 60 volts with respect to the cathodes. Initially a random discharge occurs between anode 20 and somecathode 22. When a first negative pulse, for example, of 120 volts is applied to first guides 26, the discharge region preferentially shifts in a clockwise direction to the adjacent position between anode 20 and the next clockwise first guide 26. At this time, the discharge region does not shift in a counterclockwise direction first guide 26 because it is too remote from the region already ionized.. Similarly, when a second negative pulse, for example,,of 120 volts is applied to the second guides 32 at the moment the previous pulse is terminated, the discharge region preferentiallyshifts in a clockwise direction to the adjacent position between anode 20 and the next clockwise second guide 32. Similarly, when the second negative. pulse is terminated, the discharge region preferentially shifts in a clockwise direction to the adjacentposition between anode 20 and the next clockwise cathode 22'. If the glow tube is reversible, the glow will step in counter-clockwise increments when the aforementioned pulses are applied first to second guide 32 and then to first guide 26.

An exemplary drive circuit for generating the first and second pulses referred to above is shown in Fig. 2 as comprising a counting tube 40 having first guides and second guides shown at 42 and 44, respectively. First and second guides 42 and 44 normally are held at a positive voltage so that discharge can occur only between the anode 46 and a cathode 48. Upon receiving a positive input pulse 49, half of double triode 50 produces a negative rectangular pulse 51, which is applied directly to first guides 42. This pulse also is differentiated to produce a positive pulse 52. Pulse 52, when applied to the second half of double triode 50, produces a negative rectangular pulse 54, which is applied directly to second guides 44.

Thus, one input counting pulse 49 produces two negative guide pulses 50 and 54, overlapped as indicated at 56 to shift the discharge region from one cathode to the next. Cathodes 48 are connected to output load resistors in a manner to be discussed below. At the end of a particular count, the counting tube is reset to zero by a circuit 58, which operates to raise the potential on all cathodes but the zero cathode and, therefore, to force the glow to return to that position.

A circuit embodying a plurality of counting tubes of the foregoing type in accordance with the present invention is illustrated schematically in Fig. 4. This circuit comprises one hundred counting tubes 40. Counting pulses are applied to tubes 40 by input circuits 60. Digital information in tubes 40 is read out serially by applying a carrier signal from a signal generator 61 through a single polethrow switch 63 seqeuentially to the through a common lead resistor, e.g. cathodes 62 through resistor 66, cathodes 64 through resistor 68, etc. Since counting tubes 40 essentially are characterized by constant voltage operation, the carrier signal from signal Each I formation from a selected counting Since certain changes may be made in the above de-i as -he r scribed system without departing f roin the scope at the invention herein involvedfit is intended that allmatter contained in the aboye' description shall be interpreted in an illustrative and not in a limiting sense.

What is claimed is:

1. A system for reading digital information from-counting" tubes, said counting tubes eachcomprising a common electrode and a plurality of sequence electrodes within a discharge gas, one each of the groups of corresponding sequence electrodes being connectedtogether and to one each-of a plurality of load resistors, carrier frequency generating means operatively connected to the anodes of said counting tubes, and output'means for receivingcar rier signals generated across said load resistors.

2. A system-for reading digit-al information from a plurality of counting tubes oneeach of said counting tubes comprising, within adischarge gas, an anode, a plurality. of cathodes, a plurality of first guides electrically connected togetherand a plurality of second guides electrically'connected together,'said cathodes, first guides and second guides being so interspersed that one each of said cathodes follows one each of said second guides, one each of said second guides follows one each of said first guides and one each of said first guides follow one each ofsaid cathodes, one 'each ofth e groups of corresponding cathodes bei'ngconnected together and to one each 'of a plurality ofload resistors, carrier signal generator means, switch means for connecting said carrier signal generating means s equentially to the anodes of said counting tubes, and output means for receiving carrier signals generated across said load resistors.

3. The system of claim 2 wherein, in each of said counting tubes, the cathodes, the first guides and the sec ond guides encircle the anode.

4. A system for reading digital information from a plurality of counting tubes, one each of said counting tubes comprising, within a discharge gas, an anode, a plurality of cathodes and guide means for restricting electron discharg'e'between said anode and vacathode to a Y- r re n n tea a cathodesbeing cted together and to, one eac p i at s r arid sw t i a ess a ing said carrier signal enera "n means to the anodes of eta . said counting tubssaid carrier signal being a frequency ranging from 0.5 to kc.

5. A system for reading digital information from at least one counting tube, said counting tube comprising I a common electrode and a plurality of sequence electrodes within a discharge gas, said sequence electrodes being connected to load resistors, carrier signal generat ing means operatively connected to the anode .of said counting tube, and output means for receiving carrier signals generated .across said load resistors, saidcarrier. signals being radio frequencies ranging from 0.5 kc. .to 500 kc.

'Reerences, Gited in the file of this patent UNITED STATES PATENTS 121 69 21 4 TW Ble---- AP l 2; 2 19 4%; sa rl t. at 25 news Isms- .4 a. k .5 2 FOREIGN PATENTS 715 508. re t B ta n.

A s. 2- 5 750,836; Great Britain June 20, 1956 15. 441 Great Br an sen- 5, 9

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